Distribution Of Organic Sulfur Research Articles

Research on the Composition and Distribution of Organic Sulfur in Coal.

The structure and distribution of organic sulfur in coals of different rank and different sulfur content were studied by combining mild organic solvent extraction with XPS technology. The XPS results have shown that the distribution of organic sulfur in coal is related to the degree of metamorphism of coal. Namely, thiophenic sulfur content is reduced with decreasing metamorphic degree; sulfonic acid content rises with decreasing metamorphic degree; the contents of sulfate sulfur, sulfoxide and sulfone are rarely related with metamorphic degree. The solvent extraction and GC/MS test results have also shown that the composition and structure of free and soluble organic sulfur small molecules in coal is closely related to the metamorphic degree of coal. The free organic sulfur small molecules in coal of low metamorphic degree are mainly composed of aliphatic sulfides, while those in coal of medium and high metamorphic degree are mainly composed of thiophenes. Besides, the degree of aromatization of organic sulfur small molecules rises with increasing degree of coalification.

Study on occurrence of sulfur in different group components of Xinyu clean coking coal

This paper illustrates the occurrence and distribution of sulfur in coal from the perspective of composition and structure of the coal body. With the organic sulfur-rich Xinyu clean coking coal as the sample, and the method of separating all group components from coal through extraction and stripping process as well as X-ray photoelectron spectroscopy (XPS) and gas chromatography/mass spectrometer (GC/MS) analysis techniques, the content of inorganic sulfur and organic sulfur of different forms in raw coal and various group components is studied and the occurrence of organic sulfur in organic matter of coal is carefully observed. The results show the distribution of inorganic sulfur is mainly dependent upon its particle size and density in coal and has less relationship with the structure of group components of coal. Thiophene sulfur is the major form of organic sulfur either in raw coal or group components. The external environment of molecules dominated by conjugated structure can decrease the electron binding energy of organic sulfur in conjugated structure, while increase that of sulfur in aliphatic structure. The distribution of organic sulfur in coal is balanced as a whole and will not be significantly influenced by structural differences of group components. However, the occurrence of organic sulfur compounds is associated with the structure of group components, showing relatively small difference. And there is only one type of small molecule organic sulfur compounds in light component, with small abundance.

Improved Method for Minimizing Sulfur Loss in Analysis of Particulate Organic Sulfur

The global sulfur cycle depends primarily on the metabolism of marine microorganisms, which release sulfur gas into the atmosphere and thus affect the redistribution of sulfur globally as well as the earth's climate system. To better quantify sulfur release from the ocean, analysis of the production and distribution of organic sulfur in the ocean is necessary. This report describes a wet-based method for accurate analysis of particulate organic sulfur (POS) in the marine environment. The proposed method overcomes the considerable loss of sulfur (up to 80%) that occurs during analysis using conventional methods involving drying. Use of the wet-based POS extraction procedure in conjunction with a sensitive sulfur analyzer enabled accurate measurements of cellular POS. Data obtained using this method will enable accurate assessment of how rapidly sulfur can transfer among pools. Such information will improve understanding of the role of POS in the oceanic sulfur cycle.

Synchrotron-based chemical imaging reveals plumage patterns in a 150 million year old early bird

Charles Darwin acknowledged the importance of colour in the natural selection of bird plumage. Colour can indicate age, sex, and diet, as well as play roles in camouflage, mating and establishing territories. Feather and integument colour depend on both chemical and structural characteristics and so melanosome structure and trace metal biomarkers can be used to infer colour and pigment patterns in a range of extant and fossil organisms. In this study, three key specimens of Archaeopteryx were subjected to non-destructive chemical analysis in order to investigate the potential preservation of original pigmentation in early fossil feathers. Synchrotron Rapid Scanning X-ray Fluorescence (SRS-XRF) maps are combined with sulphur X-ray Absorption Near Edge Structure (XANES) spectroscopy to provide the first map of organic sulphur distribution within whole fossils, and demonstrate that organically derived endogenous compounds are present. The distribution of trace-metals and organic sulphur in Archaeopteryx strongly suggests that remnants of endogenous eumelanin pigment have been preserved in the feathers of this iconic fossil. These distributions are used here to predict the complete feather pigment pattern and show that the distal tips and outer vanes of feathers were more heavily pigmented than inner vanes, contrary to recent studies. This pigment adaptation might have impacted upon the structural and mechanical properties of early feathers, steering plumage evolution in Archaeopteryx and other feathered theropod dinosaurs.

Occurrence and distribution of organic sulfur, silver in organic matter of the Songxi Ag–Sb deposit, South China

Occurrence and distribution of organic sulfur, silver in organic matter of the Songxi Ag–Sb deposit, South China

Reductive pyrolysis of Miocene-aged lignite lithotypes using MS and GC/MS detection systems for analysis of organic sulphur groups

The atmospheric pressure temperature programmed reduction (AP-TPR) technique, an approach for organic sulphur speciation, was extended by mass spectral detection. The coupling gave ground for precise assignment of sulphur compounds in flue gases of lignite lithotypes pyrolyzed in H 2 atmosphere. A broad range of sulphur compounds was determined, i.e. thiols, dimethylsulphide, dimethyldisulphide, CS 2, thiophenes, benzothiophenes and their alkylated homologues. Certain peculiarities in organic sulphur distribution in lithotypes under study were noticed. Humovitrain was the lithotype with the highest organic sulphur content. A preponderance of aliphatic sulphur, thiols and dimethylsulfides were determined for both homogeneous lithotypes (xylain and humovitrain). In humovitrain, additionally thiophenes were also identified. For heterogeneous lithotypes, liptain and humoclarain, a dominance of disulphides and an almost lack of sulphides was observed. This is an indication that with coalification a gradual loss of aliphatic sulphur functions has proceeded, where more resistant disulphides sulphur bridges turned out to be present. Thiophenes are the most abundant aromatic structures, dominating in humoclarain. Some amounts of oxidised organic sulphur compounds (1% up to 4.1% of S org) were semi-quantitative determined in lithotypes using AP-TPR-MS.

SEM-EDX and isotope characterization of the organic sulfur in macerals and chars in Illinois Basin coals

Two samples of the Herrin (Illinois No. 6) Coal and one sample of the Colchester (Illinois No. 2) Coal from the Illinois Basin were studied to evaluate the spatial distribution of organic sulfur within macerals occurring next to pyrite grains, both in the raw coal and their chars. The chars were produced by pyrolysing the coal at 250–550°C in a nitrogen atmosphere. Representative splits of the coals and their chars were mounted in epoxy and polished for optical microscopy and scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX). Determinations of organic sulfur concentrations were made at 996 locations within macerals, mostly vitrinite, around 115 grains of pyrite and at 50 locations around 5 pores in chars. The pyrite considered here is restricted to the disseminated type within macerals. On the average, the organic sulfur content increased near pyrite grains after the coals were charred at 550°C, indicating that some of the pyritic sulfur released during charring was retained within the organic matrix rather than being emitted to the atmosphere. One of the coal samples and its chars were isotopically characterized by chemically separating the pyritic and organic sulfur fractions, followed by analyzing the isotopes of the sulfur forms with a Nuclide 6–60 ratio mass spectrometer. The sulfur isotope (δ 34S) data confirmed the movement of pyritic sulfur into the macerals after charring to 550°C. About 18% of the organic sulfur that remained in the 550°C char had originally been pyritic sulfur in the untreated coal.

Distribution of Organic Sulfur in Macerals of the Herrin Coal Under Marine and Transitional to Nonmarine Shales

Distribution of Organic Sulfur in Macerals of the Herrin Coal Under Marine and Transitional to Nonmarine Shales

Variation of organic sulfur in macerals of selected Illinois Basin coals

An electron microbeam technique was used to determine the distribution of organic sulfur in the main macerals of five Illinois Basin coals. On average, sporinites are the highest, inertinites the lowest, and vitrinites intermediate in organic sulfur for each coal. The observed differences are likely due to varying affinities of the different pre-maceral materials for sulfur and/or local variation in the production of H 2S primarily during the peat stage. Investigation of molecular structures of individual macerals in relation to the findings of this study may delineate the relative abundance of organic sulfur in various organic compounds and thus lead to the development of efficient desulfurization processes.

芦別炭鉱炭層内の硫黄の分布

The distribution of forms of sulfur in five palaeogene coal seams of the Ashibetsu colliery in the Ishikari coalfield was investigated in relation to the depositional environment of coal. The main parts of these coal seams contain low amounts of total sulfur. Sulfate and pyritic sulfur contents are very low in the middle part and increase sharply near the top of every coal seam. Some coal seams contain high or somewhat high amounts of inorganic sulfur near the floor. The distribution of organic sulfur is not so simple as that of inorganic sulfur, but there is a tendency for the content of organic sulfur to be high towards the roof. It is not clear why the content of organic sulfur in the lower part of one coal seam is high although the content of inorganic sulfur is very low in the same part.The variations in sulfur of coal seams are interpreted to depend on whether the coal formation developed under marine condition or fresh water condition. Especially pyritic sulfur content can be one of the important indicators of the depositional environment. It is estimated from the distribution of forms of sulfur in five coal seams of the Ashibetsu colliery that these coal formations began on the way to limnic environment or under fresh water condition influenced by marine regression, developed fundamentally in limnic basins and terminated under brackish water condition influenced by marine incursion. This transition is clearly in harmony with the cyclothem, sand→mud→coal→mud, as seen at the time of the deposition of coal seams in the Ishikari coalfield.